1. Field
Embodiments described generally relate to nozzles for fluidizing particulates. More particularly, such embodiments relate to plug resistant nozzles for fluidizing particulates.
2. Description of the Related Art
Gasification is a high temperature process usually conducted at elevated pressure to convert carbon-containing materials into carbon monoxide and hydrogen gas. Since this gas is often used for the synthesis of chemicals or synthetic hydrocarbon fuels, the gas is often referred to as “synthesis gas” or “syngas.” Syngas can be used as a fuel to generate electricity or steam and as a source of hydrogen.
During the gasification process, a fluid/particulate mixture flows through one or more fluid conveying structures in a gasifier. The fluid conveying structures typically include a pressure shell and a refractory layer disposed on an inner surface of the pressure shell. Conventional nozzles extend through the pressure shell and the refractory layer and introduce a fluid, e.g., a gas, into the fluid/particulate mixture to fluidize the particulates so that they will continue to flow through the fluid conveying structure.
When the gasification process experiences interruptions, such as an unscheduled shutdown, however, the fluid introduced via the nozzles can be stopped. This can allow the particulates in the fluid conveying structure to descend to the inner surface of the refractory layer, where the particulates tend to accumulate in the nozzles. When the particulates accumulate in the nozzles, it is desirable to blow the particulates out of the nozzles rather than rodding or drilling them out, as the rodding and drilling procedures are significantly more time consuming. However, since conventional nozzles must be long enough to extend through the pressure shell and the refractory layer, the particulate blockage tends to be too great to blow out.
There is a need, therefore, for improved systems and methods for fluidizing particulates in a gasifier while resisting significant nozzle build-up.